Digital polar transmitter (DPTX) architectures are very attractive for modern radios, because such architectures can provide improved area and power consumption characteristics compared with conventional analog architectures. For a polar transmitter utilizing a signed radius, trajectories which pass through the origin can be handled by switching the sign of the radius path at the moment of the zero crossing. This partly solves a well known problem of polar transmit architectures, where the handling of zero crossing trajectories is one of the main issues. The farther away from the origin the signal trajectory passes the more difficult the definition of the time stamp of the sign change in the polar path. Methods have been developed that use signal processing to force the signal close to the origin. These methods, especially when applied using a current saving low sample rate, have limited accuracy. (e.g., the signal trajectory can pass the origin at some distance, instead of as wanted, through the origin.) Further actions can be taken to try to avoid a sample point that is located very close to the origin. A case where the trajectory passes very close to the origin and one sample point is located close to the perpendicular projection of the origin can render two consecutive phase steps of around 90°. Without special actions, unsigned to signed polar transformation will not give provide an advantage since there is no well-defined time interval to apply the switch of signs in the radius signal.